Preheat oven to 350 degrees Fahrenheit and lightly grease a 9"x13" pan. In the bowl of an electric mixer, cream together butter, brown sugar, white sugar, eggs, vanilla and peanut butter.
In a separate bowl, stir together flour, oats, baking soda and salt. Add dry mixture to wet mixture and mix until combined. Quickly mix in butterscotch and chocolate chips.
Press dough into prepared pan, sprinkle with 1/4 c. each of butterscotch and chocolate chips and press into the dough, then bake for approximately 14-15 minutes or just until set. Don't overbake or they'll be dry!